maka nilai a dan b berturut turut adalah

f(x) = ax + b
f(2) = 2a + b = 1
f(1) = a + b = 2

a + b = 2
a = 2 - b

substitusi ke 2a + b = 1

2 ( 2-b ) + b = 1
4 - 2b + b = 1
-b = 1-4
-b = -3
b = 3

subs b=3 ke a = 2 - b

a = 2 - 3 = -1

C. -1 & 3